This renewal application for a Mid-Career Investigator Award in Patient-Oriented Research for Josiah D. Rich, MD, MPH, Professor of Medicine and Community Health at Brown Medical School will allow the continuation of protected time for research and mentoring at the leading edge of addiction and infectious diseases among criminal justice-involved populations. The past four years of the current K24 have enabled the development and maintenance of a strong research program with a documented record of independent peer-reviewed support for patient-orientated research (three new R01s and an R21). In this same time, Dr. Rich co-authored 43 peer-reviewed scientific papers and three book chapters and presented at numerous national and international meetings. Current funded research activities are focused on 1) linkage to methadone treatment after release from incarceration; 2) linkage to HIV care after release; 3) HIV testing and linkage to treatment during probation/parole; and 4) training and provision of naloxone upon release from incarceration to prevent fatal overdose. All of these projects provide ample opportunities for mentorship. With the backing of an institution that highly values and supports mentorship, the candidate has successfully mentored over 25 junior investigators, who have generated numerous coauthored manuscripts and been awarded three K awards; two R21s; and three R01s in the last four years. The goals for a renewed K24 are to: 1) build further on current work with correctional facilities and other branches of the criminal justice system as settings for highy effective patient-oriented research in HIV and addiction care that focuses on the populations most at risk; 2) mentor junior investigators at all levels to prepare the next generation of researchers and practitioners for ethical, innovative, and rigorous research with, and on behalf of, the populations most at risk of HIV and addictions; and 3) advance the field of research by bridging research and policy to improve the plight of criminal justice-involved populations, especially in the overlap between addiction and infectious diseases. This proposal capitalizes on the existing resources at an institution with an outstanding clinical research environment, strong institutional commitment, supportive colleagues, and an abundance of eager, high-quality potential mentees. The Division of Infectious Diseases at The Miriam Hospital, a teaching hospital of Brown Medical School, includes the AIDS International Training and Research Program, the Center for Drug Addiction and AIDS Research, multiple funded training grants, the Center for Prisoner Health and Human Rights, and the Prisoner Health Scientific Program of the Lifespan/Tufts/Brown Center for AIDS research. This award will protect time for mentorship and research that would otherwise be diverted to administrative and clinical duties.